Method for biological purification

ABSTRACT

An apparatus is disclosed for containing a microorganism culture in an active exponential growth and delivering a supply of microorganisms to an environment containing wastes for bio-augmenting the biodegradation of the wastes. The apparatus comprises a bioreactor and an operably connected controller. The bioreactor has a bioreactor chamber for containing a supply of microorganisms, a second chamber for containing a supply of water and inorganic nutrients, and a third chamber for containing a supply of organic nutrients. The bioreactor is operably connected to the controller in which a first pump is operably connected in fluid communication between the bioreactor chamber and the second chamber and third chamber, and a second pump is operably connected in fluid communication between the bioreactor chamber and the environment containing wastes to be biodegraded. The controller further includes a timer and regulator operably connected to the first and second pumps to effectively maintain the microorganisms in exponential growth in the bioreactor chamber and to deliver microorganisms to an environment to be treated. Also, disclosed is a method for bio-augmenting the biodegradation of wastes.

This is a continuation of application Ser. No. 09/199,241 filed Nov. 24,1998, now abandoned, which in turn is a continuation of application Ser.No. 08/867,946 filed Jun. 3, 1997, now U.S. Pat. No. 5,840,182 issuedNov. 24, 1998, which in turn is a continuation of application Ser. No.08/613,125 filed Mar. 8, 1996, now abandoned.

This invention was made with Government support under contract numberDE-AC02-76CH00016, between the U.S. Department of Energy and AssociatedUniversities, Inc. The Government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for biologicalpurification of wastes. More particularly, the invention is directed toan apparatus and method for treatment of wastes, such as grease andother contaminants contained in waste water streams, ground water, soil,etc., by introducing living organisms to biodegrade the wastes.

Wastes, under normal conditions, are gradually broken down orbiodegraded by indigenous microorganisms in the environment. However,biodegradation reactions are often hindered by environmentalfluctuations such as changes in temperature, pH, salinity, water and airsupply, etc. For example, wastes such as fat and grease are biodegradedby microorganisms to fatty acids and glycerol. In the presence of oxygenthe fatty acids are further metabolized with the end product beingcarbon dioxide. Glycerol is also metabolized as an efficient energysource.

Waste water systems, for example those in the food service industry,typically incorporate a grease trap to trap grease and othercontaminants from the passing flow of waste water and to store suchcontaminants for eventual removal from the trap. Typically, the greasetrap is accessed periodically and the contaminants removed for eventualdisposal. Grease and other contaminants often build up very quickly insuch traps. If they are not removed in a timely fashion, the ability ofthe trap to operate efficiently, or at all, is seriously affected. Whena trap is no longer functional, the contaminants will bypass the trapand flow into areas which are intended to be free from thesecontaminants. Specifically, the contaminants will either clog up thewaste water system or will flow into the municipal sewer system inviolation of local ordinances or state laws. Most grease traps requirerelatively large compartments, particularly if the associated foodservice facility operates on a large volume.

A variety of approaches have been developed to increase the requiredperiod between subsequent cleanings of a grease trap by increasing thebiodegradation by microorganisms of grease in the trap. One approach toenhancing biodegradation of grease in a grease trap is to introducechemicals or nutrients to the trap to aid naturally occurring bacteriaor microorganisms in the trap. For example, U.S. Pat. No. 5,340,376granted to Cunningham discloses a controlled-release nutrient sourcethat adds nutrients at low levels to a bioremediation environment toenhance microorganism growth and activity and promote the effectivenessof the bioremediation in removing environmental contaminants. Thenutrients are in the form of coated solid particles, each having a coreof water soluble microorganism nutrients encapsulated in a releaserate-controlling coating. The effectiveness of bioremediation of wastesby enhancing the growth of naturally occurring bacteria ormicroorganisms with the introduction of a controlled-release nutrientsource is still hindered due to environmental fluctuations such aschanges in temperature, pH, salinity, water and air supply, etc.

Another approach to enhancing biodegradation of grease in a grease trapis to introduce a structure upon which indigenous microorganisms canbind and grow, and thus effectively remain in the grease trap. Forexample, U.S. Pat. No. 4,925,564 and U.S. Pat. No. 4,670,149 bothgranted to Francis disclose a bacterial incubator device having anenclosure with a foraminous wall structure packed with high surface areaelements such as spherical packing of a shape or size to multiply thesolid bacterial growth surface area in a grease trap. The incubator ispositioned at the interface of floating grease and water. Similarly, theeffectiveness of bioremediation of wastes by enhancing the growth ofnaturally occurring bacteria or microorganisms with the introduction ofa support structure is often hindered due to environmental fluctuationssuch as changes in temperature, pH, salinity, water and air supply, etc.

Still another approach to enhancing biodegradation of grease in a greasetrap is to introduce additional microorganisms into the grease trap. Forexample, U.S. Pat. No. 5,271,829 granted to Heppenstall discloses atreatment system for waste water which includes a dispenser forintroducing treatment material, a solution of bacteria, into a greasetrap for the purpose of digesting the grease which is separated fromwaste water as it flows through the grease trap. The dispenser includesa housing having a compartment for holding a quantity of greasedigesting material and a dispensing opening at the lower end of thecompartment. A restricter is located at the dispensing openingpermitting the digesting material to pass at a constant restrictive ratefrom the dispensing opening to the grease to be treated in a chamber ofthe grease-trap. The grease digesting material in the dispenser willnaturally go through a four phase growth cycle (i.e., lag, exponential,stationary, and death, further described in detail in a Bacterial GrowthSection below) which limits its effectiveness of enhancing thebiodegradation of grease on an extended or continuous basis.

Another example of introducing additional microorganisms in to a greasetrap is U.S. Pat. No. 5,225,083 granted to Pappas, et al. Pappas, et al.discloses a simple method that includes adding endemic bacterialmicroorganisms to one or more of the drain lines for ultimateintroduction into the grease trap and biodegrading grease. Depending onthe bacterial microorganisms growth cycle phases, the effectiveness ofthe biodegradation of grease by the microorganisms will vary.

Another approach to enhancing biodegradation of grease in a grease trapis to introduce enzymes into the grease trap to solubilize the grease.For example U.S. Pat. No. 4,940,539 granted to Weber discloses a greasetrap comprising a housing having an inlet to receive waste watercontaining grease and an outlet. The waste water within the housing isheated by an electric heating element which is immersed in the wastewater and the heating element is controlled by a thermostat to maintaina desired temperature of the water within a given range. An aqueouscomposition containing a mixture of enzymes and bacterial spores isintroduced into the housing into contact with the waste water. Theenzymes solubilize the grease while the bacteria spores biodegrade thegrease. However, the ability of the bacteria to biodegrade waste will bedelayed in that the bacterial spores first enter a lag phase requiring aperiod of time before entering an exponential growth phase in which tobegin biodegradation of the waste.

Another example, U.S. Pat. No. 4,882,059 granted to Wong, et al.discloses a method for solubilizing particulate materials in waste waterwhich comprises the steps of cultivating aerobic bacteria in thepresence of oxygen in an activator solution containing a food sourceuntil the level of the food source drops below a predetermined levelcausing the bacteria to begin producing increased amounts of enzymes andthereafter contacting the activated bacteria and enzymes with theparticulate materials under conditions which solubilize the waste.Another example, shown in U.S. Pat. No. 5,171,687 granted to Moller, etal., discloses an apparatus for culturing and delivering microbes forwaste treatment in a flow system. The apparatus includes a containerhaving a first and second chambers. The first chamber is maintained in anutrient rich environment for the source microbial matter supportedtherein while the second chamber is nutrient deficient. Water isintroduced into the first chamber at a predetermined rate and flowsthrough an outlet into the second chamber. The outlet of the secondchamber is directed to a flow system benefiting from the activity of themicrobial matter. In both Wong and Moller, et al., it is believed thatstarving the bacteria of nutrients activates enzyme production thereinto aid in solubilizing particulate materials in waste water. Although,the enzymes aid in solubilizing the grease, the bacteria will beineffective in biodegrading the solubilized grease in that the bacteriabeing nutrient deficient will enter a stationary phase (if not deathphase) necessitating that the bacteria enters a lag phase, requiring aperiod of time before the bacteria enters an exponential growth phase inwhich to begin to biodegrade the grease.

There is a need for a bio-augmentation system for use in a wastetreatment facility in which the system maintains microorganisms in anactive exponential growth and at a predetermined concentration,desirably a maximum concentration, and that further delivers activemicroorganisms on a continuous or periodic basis into contact with anenvironment containing wastes for effectively bio-augmenting thebiodegradation of the wastes contained in the environment.

SUMMARY OF THE INVENTION

Accordingly it is an object of the present invention to provide, in awaste treatment facility, a bio-augmentation system that adjusts theenvironment to be treated to a condition that is more conducive tobiodegradation of the treated waste by introduction of acclimatedbacteria or microorganisms designed for that purpose.

It is another object of the present invention to provide abio-augmentation system that maintains microorganisms in an activeexponential growth and acclimated to an environment to be delivered, anddeliver the microorganisms to an environment containing wastes forefficiently and quickly biodegrading the wastes.

It is also an object of the present invention to provide abio-augmentation system that introduces microorganisms into anenvironment to be treated to ensure long-term maintaining,supplementing, and reconditioning of the biodegradation process for peakperformance or restarting the biodegradation process should the normalrate of biodegradation stall in the environment to be treated.

It is still another object of the present invention to provide abio-augmentation system that injects microorganisms into a waste flowsystem, e.g., a grease trap, which greatly increases the normallyrequired time between removal of accumulated grease.

It is still another object of the present invention to provide abio-augmentation system for use in conjunction with a grease trap andwhich reduces the size of the required grease trap for effectivelyremoving grease from waste water before discharge of the waste waterinto a municipal sewer system as permitted under local environmentalordinances or state laws.

It is yet another object of the present invention to provide abio-augmentation system for use in waste treatment in which the systemovercomes the problems hindering the effectiveness of biodegradationassociated with environmental fluctuations such as changes intemperature, pH, salinity, water and air supplies, etc.

It is still another object of the present invention to provide abio-augmentation system for use with various waste treatment facilities,such as drain lines, leach ponds, septic systems and lift stations, forbio-remediating waste water streams, and ground water and soilcontamination.

It is a further object of the present invention to provide abio-augmentation system for biological purification of wastes which issimple in construction and which is inexpensive, and which is capable ofa long life of useful service with a minimum of maintenance.

It is an object of the present invention to provide a method forculturing and delivering microorganisms in exponential growth to anenvironment for biodegradation of wastes contained in the environment.

Certain of the foregoing and related objects are readily obtained in abio-augmentation apparatus for containing a microorganism culture anddelivering a supply of microorganisms to an environment containingwastes for bio-augmenting the biodegradation of the wastes, in which theapparatus comprises a first container having a bioreactor chamber forcontaining a microorganism culture and an operably connected controller.The controller includes a means for introducing a predetermined supplyof water to the bioreactor chamber, and for introducing a predeterminedsupply of at least one of inorganic nutrients and organic nutrients tothe bioreactor chamber, and means for removing a preselected supply ofwater, at least one of inorganic nutrients and organic nutrients, andmicroorganisms from the bioreactor chamber so that the controller iseffective to maintain such microorganism culture in substantiallyexponential growth in the bioreactor chamber, and means for deliveringsuch a removal preselected supply of water, at least one of inorganicnutrients and organic nutrients, and microorganisms in substantiallyexponential growth into contact with an environment containing wastesfor biodegradation of the wastes.

Preferably, the bio-augmentation apparatus includes means forintroducing a predetermined supply of oxygen to the bioreactor chamber.Desirably, the means for introducing a predetermined supply of water tothe bioreactor chamber, and for introducing a predetermined supply of atleast one of inorganic nutrients and organic nutrients to the bioreactorchamber, and the means for removing a preselected supply of water, atleast one of inorganic nutrients and organic nutrients, andmicroorganisms from the bioreactor chamber so that the controller iseffective to maintain the microorganisms in the bioreactor chamber insubstantially exponential growth, is either periodically operable orcontinuously operable. Advantageously, the means for introducing apredetermined supply of water to the bioreactor chamber, and forintroducing a predetermined supply of at least one of inorganicnutrients and organic nutrients to the bioreactor chamber, and the meansfor removing a preselected supply of water, at least one of inorganicnutrients and organic nutrients, and microorganisms from the bioreactorchamber, is operable to introduce and remove, respectively,substantially the same volumetric supplies.

In an preferred embodiment of the present invention, thebio-augmentation apparatus includes a second container having a secondchamber for containing a supply of water and inorganic nutrients inwhich the second chamber is operably connected in fluid communicationwith the bioreactor chamber, and a third container having a thirdchamber for containing a supply of organic nutrients in which the thirdchamber is operably connected in fluid communication with the bioreactorchamber. The first container includes a circular bottom and an upwardlyextending cylindrical side wall, the second container includes acircular bottom and an upwardly extending cylindrical side wall, and thethird container includes a circular bottom and an upwardly extendingcylindrical side wall.

Desirably, the first container is disposed within the second container,the third container is disposed within the bioreactor chamber, and thesecond chamber is annular in shape.

In another preferred embodiment of the present invention of thebio-augmentation apparatus, the means for introducing a predeterminedsupply of water to the bioreactor chamber, and for introducing apredetermined supply of at least one of inorganic nutrients and organicnutrients to the bioreactor chamber, includes a first pump operablyconnected in fluid communication between the bioreactor chamber and thesecond chamber, and the means for removing a preselected supply ofwater, at least one of inorganic nutrients and organic nutrients, andmicroorganisms and means for delivering the removed preselected supplyof water, at least one of inorganic nutrients and organic nutrients, andmicroorganisms into contact with an environment containing wastes to bebiodegraded, includes a second pump operably connected in fluidcommunication between the bioreactor chamber and the environmentcontaining wastes to be biodegraded.

Desirably, the controller includes a timer and a regulator operablyconnected to the first pump and second pump to effectively maintain themicroorganisms in substantially exponential growth in the bioreactorchamber.

Certain of the foregoing and related objects are also readily obtainedin a method for bio-augmenting the biodegradation of wastes. The methodincludes the steps of: providing one of inorganic nutrients and organicnutrients to the microorganism culture, removing a preselected supply ofwater, at least one of inorganic nutrients and organic nutrients, andmicroorganisms from the microorganism culture so that the microorganismculture is maintained in substantially exponential growth, anddelivering the removed preselected supply of water, at least one ofinorganic nutrients and organic nutrients, and microorganisms intocontact with an environment containing a waste for biodegrading thewaste.

Preferably, the microorganisms are at least one of anaerobic and aerobicmicroorganisms, and the at least one inorganic nutrients and organicnutrients are substantially similar to wastes contained in the waste tobe biodegraded so as to acclimate the microorganisms to the waste to bebiodegraded. Advantageously, the microorganism culture is maintained insubstantially exponential growth midway between a lag phase and astationary phase. Desirably, the microorganism culture is maintained ina bioreactor chamber at a concentration of about 500 million cells/cubiccentimeter to about 3 billion cells/cubic centimeter. More desirably,the microorganism culture is maintained in a bioreactor chamber at aconcentration of about 2.5 billion cells/cubic centimeter.

Preferably, the step of introducing a predetermined supply of water andat least one of inorganic nutrients and organic nutrients to themicroorganisms culture and the step of removing a preselected supply ofwater, at least one of inorganic nutrients and organic nutrients, andmicroorganisms from the microorganism culture so that the microorganismculture is maintained in substantially an exponential growth, are eitherperiodically or continuously performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the present invention will become apparentfrom the following detailed description considered in connection withthe accompanying drawings, which disclose several embodiments of theinvention. It is to be understood that the drawings are to be used forthe purpose of illustration only and not as a definition of the limitsof the invention.

In the drawings, similar reference characters denote similar elementsthroughout the several views.

FIG. 1 is a perspective view of a preferred embodiment of an apparatusof the present invention which generally includes a bioreactor operablyconnected to a controller;

FIG. 2 is an enlarged perspective view, partially broken away, of thebioreactor of FIG. 1;

FIG. 3 is a graphical representation of a typical four phase bacterialgrowth cycle (i.e., lag, exponential, stationary, and death) of amicroorganism culture in which no additional culture medium is added;

FIG. 4 is a diagrammatic illustration of the bio-augmentation apparatusof FIG. 1;

FIGS. 5(a) and 5(b) are graphical results using optical densitymeasuring means for periodically sampling (a) a microorganism culturewhich shows the various lag, exponential and stationary growth cyclephases of the microorganism culture and (b) a microorganism culturemaintained in the bio-augmentation system of FIG. 1 in which themicroorganism culture is maintained in exponential growth; and

FIG. 6 is a flow chart illustrating the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Apparatus

Turning now to the drawings and in particular to FIG. 1, thereinillustrated is a bio-augmentation apparatus 10 embodying the presentinvention. Apparatus 10 generally includes a bioreactor 12 forcontaining a microorganism culture (not shown) in which bioreactor 12 isoperably connected to a controller 20 via tubes 22, 24, 26, 28 foreffectively maintaining the microorganism culture in exponential growthand for delivering microorganisms via tube 29 to an environmentcontaining wastes for bio-augmenting the biodegradation of the wastes,e.g., grease in a grease trap or septic tank (not shown). The operationof apparatus 10 is explained in greater detail in an Operation Sectionbelow.

Referring to FIG. 2, bioreactor 12 includes a first container 30 havinga circular bottom 32 and an upwardly extending cylindrical side wall 34.A removable lid 36 is attached to the upper end of side wall 34 andcloses container 30. Surrounding first container 30 is a secondcontainer 40 having a circular bottom 42 and an upwardly extendingcylindrical side wall 44. A removable lid 46 is attached to the upperend of side wall 44 and closes container 40.

Defined within first container 30 is a cylindrical bioreactor chamber 14for containing a microorganism culture (not shown). Defined betweenfirst container 30 and second container 40 is an annular storage orsecond chamber 16 for containing a supply of water and inorganicnutrients, such as potassium phosphate, ammonium nitrite and calciumchloride.

Preferably, containers 30 and 40 are fabricated from a plastic materialthat is nontoxic and does not react with the microorganisms, such aspolyethylene or polyvinyl chloride. Although bioreactor 12 is shown in acompact configuration, it will be appreciated that containers 30 and 40can be square or rectangularly shaped and disposed in side by siderelationship.

A third container 50 having a third chamber 18, for containing a supplyof organic nutrients (not shown) or carbon source such as compacted drypotassium-oleate powder or other water soluble salts of fatty acids, isdisposed within bioreactor chamber 14 and supported above themicroorganism culture. Desirably, the supply of organic nutrients issimilar to that of the waste to be biodegraded so as to acclimate themicroorganisms in the microorganism culture (not shown) to the waste tobe biodegraded. Specifically, container 50 is cylindrically shapedhaving an a circular bottom 52 and an upwardly extending cylindricalside wall 54. The upper end of cylindrical side wall 54 receives arubber stopper 58 that attaches to tube 26 for receiving a supply ofwater and inorganic nutrients. A longitudinally extending slit 56 incontainer 50 permits organic nutrients contained in chamber 18 to bedissolved by a supply of water and inorganic nutrients as they passthrough chamber 18 and discharge into bioreactor chamber 14. Again,although bioreactor 12 is shown in a compact configuration, it will beappreciated that container 50 need not be placed inside bioreactorchamber 14 but could consist of a separate stand alone unit oralternatively the supply of organic nutrients could be suitablyincorporated in-line with tube 26.

Referring again to FIG. 1, controller 20 effectively maintains themicroorganism culture in substantially exponential growth in bioreactor12 and delivers active microorganisms to an environment to be treated.Specifically, controller 20 controls delivery of a predetermined supplyof water, inorganic nutrients, organism nutrients and air intobioreactor 12 and controls removal of a preselected supply or water,inorganic nutrients, organic nutrients and active microorganisms frombioreactor 12.

Means 60 for introducing a predetermined supply of oxygen to bioreactor12 includes an air pump 62 connected to tube 22. Specifically, tube 22is connected at one end to air pump 62, and as shown in FIG. 2, theopposite end passes through cover 36 and cover 46 so that the oppositeend is positioned adjacent bottom 32 of container 30 in bioreactorchamber 14.

Referring again to FIG. 1, means 70 for introducing a predeterminedsupply of water (not shown) from second chamber 16 (FIG. 2) tobioreactor chamber 14 (FIG. 2), and for introducing a predeterminedsupply of organic nutrients (not shown) from third chamber 18 (FIG. 2)to bioreactor chamber 14 (FIG. 2), includes a first pump 72, tubes 24and 26, timer 100 and regulator 110. Specifically, as shown in FIG. 2,tube 24 has a free end disposed adjacent bottom 32 of container 30 forreceiving a predetermined supply of water and inorganic nutrientcontained in second chamber 16 and the other end of tube 24 is attachedto an input port on pump 72 (FIG. 1). An output port of pump 72 (FIG. 1)is attached to one end of tube 26 and the opposite end of tube 26 passesthrough lid 36, lid 46 for connection to stopper 58 in container 50.

As shown in FIG. 1, the amount or flow of water removed from secondchamber 16 (FIG. 2) and discharged into bioreactor chamber 14 (FIG. 2)is controlled by timer 100 operably connected via wires to pump 72 toturn pump 72 on and off, and regulator 110 is operably connected viawires to pump 72 to adjust the supply of electrical energy to pump 72thereby to control the speed of pump 72 and thus the flow rate of waterwhen pump 72 is activated. Although, water can be supplied from amunicipal water source, it is desirable to include in the supply ofwater various inorganic nutrients.

Means 80 for removing water, inorganic nutrients, organic nutrients, andmicroorganisms from bioreactor 12 so as to effectively maintain theremaining microorganism culture in exponential growth includes a secondpump 82, tube 28, timer 100 and regulator 110. Specifically, as shown inFIG. 2, tube 28 has a free end disposed adjacent bottom 42 of container40 for receiving a preselected supply of water, inorganic nutrients,organic nutrients, and microorganisms contained in bioreactor chamber 14and an opposite end of tube 28 is attached to an input port on pump 82(FIG. 1).

Referring again to FIG. 1, means 90 for contacting the removalpreselected water, inorganic nutrients, organic nutrients, andmicroorganisms delivered via tube 28 of means 80 with an environmentcontaining wastes, includes pump 82 and tube 29. Specifically, as shownin FIG. 2, tube 29 has one end attached to an output port on pump 82(FIG. 1) and an opposite end operably connected to a drain or trap (notshown) for discharging a preselected amount of the contents ofbioreactor chamber 14 containing water, inorganic nutrients, organicnutrients, and microorganisms.

The amount of flow of water, inorganic nutrients, organic nutrients, andmicroorganisms, from bioreactor chamber 14 (FIG. 2) to a trap (notshown) is controlled by timer 100 operably connected via wires to pump82 to turn pump 82 on and off, and regulator 110 operably connected viawires to pump 82 to adjust the supply of electrical energy to pump 82thereby to control the speed of pump 82 and thus the flow rate of water,inorganic nutrients, organic nutrients, and microorganisms, when pump 82is activated. Air pump 62, timer 100 and regulator 100 are operablyconnected to an electrical outlet, preferably 120 volts A.C. (notshown).

Bacterial Growth

A key factor of the present invention is the ability to retain theacclimated microorganism culture in exponential growth (also known aslogarithmic growth) where the microorganisms, i.e., the number of cells,increase in a direct proportion to time or divide at a constant rate,and thus are most active, and to deliver active microorganisms to anenvironment to be treated.

Specifically, referring to FIG. 3, therein is illustrated a typicalgrowth cycle showing four distinct phases in the cycle of a cultureunder constant condition, i.e. no additional culture medium (organic andinorganic nutrients) are added for the growth of microorganisms in theculture. The four illustrated growth phases are; lag, exponential,stationary, and death. In the lag phase the number of cells does notincrease and the cells are preparing for active growth. Eventually, celldivision occurs and an exponential growth phase is reached. Finally,either some nutrients become exhausted or some toxic metabolic productsaccumulate, and the growth rate decreases and growth ceases.

In the present invention it is desired to retain the acclimatedmicroorganism culture in exponential growth where the microorganisms aremost active, and to deliver the active microorganisms to an environmentto be treated in which the microorganisms immediately begin tobiodegrade the waste.

It is not desirable to have the microorganisms delivered to anenvironment to be treated in which the microorganisms are in a lag phaserequiring a period of time before the microorganisms reach exponentialgrowth in which to begin biodegradation of the waste. For example, ifthe environment to be treated is a grease trap having a periodic orconstant fluid flow, the microorganisms will be washed away or removedfrom the grease trap before being able to biodegrade the waste.

Nor is it desirable to have the microorganisms delivered to anenvironment to be treated in which the microorganisms are in astationary phase and become stressed which upon delivery of themicroorganisms into an environment to be treated require themicroorganisms to enter a lag phase and require a period of time beforeentering exponential growth. Again, for example, if the environment tobe treated is a typical grease trap having a periodic or constant fluidflow the microorganisms will be washed away or removed from the greasetrap before being able to biodegrade the waste.

Operation

The operation of the present invention will be explained with respect toFIG. 4, a diagrammatical illustration of bio-augmentation apparatus 10for culturing microorganisms in exponential growth and for deliveringmicroorganisms to an environment containing wastes for bio-augmentingthe biodegradation of the wastes, e.g., grease in a grease trap 120.

In set-up of apparatus 10, covers 36 and 46 of bioreactor 12, shown inplace, are removed and an initial microorganism culture 200 consistingof microorganisms and a culture medium of water, inorganic nutrients andorganic nutrients, is placed in bioreactor chamber 14 of first container30. Preferably aerobic or anaerobic bacteria, which are either naturallyoccurring or developed specifically for biodegradation of the specificwaste in a environment to be treated, is suitable for use with thepresent invention.

A predetermined supply of water or water and inorganic nutrients 210 isplaced in second chamber 16 of second container 40. A supply ofdissolvable organic nutrients 220 is packed inside container 50. Covers36 and 46 are replaced.

The free end of tube 29 is connected to generally the starting point ofthe waste stream for example a drain (not shown) leading into a greasetrap 120 or directly into grease trap 120.

Once the microorganism culture 200 reaches exponential growth,controller 20 is activated to maintain the microorganism culture inexponential growth and deliver microorganisms to an environment to betreated in which the microorganisms are exponentially growing, and thusare at peak performance for biodegrading the waste contained in theenvironment to be treated.

Referring again to FIG. 4, specifically, controller 20 is set-up tocontrol the rate of water, inorganic nutrients, and organic nutrientsinto bioreactor chamber 14 and control the rate of water, inorganicnutrients, organic nutrients, and microorganisms out of bioreactorchamber 14 and delivered to the environment to be treated, e.g., greasetrap 120. A number of variables are involved in maintaining themicroorganism culture in exponential growth. Such variables are the typeof microorganism and its specific growth rate, the volume of theculture, the initial culture medium, the rate of introduction of water,inorganic nutrients, and organic nutrients into the microorganismculture, and the rate of removal of water, inorganic nutrients, organicnutrients, and microorganisms from the microorganism culture which isdelivered to an environment to be treated.

Given a certain type of microorganism having a specific growth rateconstant, a certain volume of culture, and an initial culture medium,the microorganism culture can be monitored to determine the number ofcells in the microorganism culture, i.e., periodically conventionallymeasuring the optical density of samples taken from the culture. Themicroorganism culture will go through a lag, exponential and stationaryphases. By setting-up controller 20, the rate of introduction of water,inorganic nutrients, and organic nutrients into the microorganismculture, and the rate of removal of water, inorganic nutrients, organicnutrients, and microorganisms from the microorganism culture anddelivered to an environment to be treated can be adjusted to maintainthe microorganism culture in exponential growth before the microorganismculture reaches the stationary phase.

The rate of introduction of water, inorganic nutrients, and organicnutrients into the microorganism culture, and the rate of removal ofwater, inorganic nutrients, organic nutrients, and microorganisms fromthe microorganism culture and delivered to an environment to be treatedcan be either at a continuous rate or accomplished periodically.Desirably, the rate (volume per time) of the introduction and removalwill be substantially volumetrically the same whether controller 20 isoperated in a continuous or periodic mode. That is, pumps 72 and 82 willbe operated simultaneously.

To increase the activity in bioreactor chamber 14, a mixer 140 such as astirrer or paddle can be operably installed in bioreactor chamber 14. Inaddition, a mixer 145 such as a stirrer or paddle can also be placed ingrease trap 120 to increase the contact of microorganisms to the grease.

EXAMPLE

Referring to FIG. 5(a), there is graphically illustrated the opticaldensity versus time results of an initial three day experiment thatdetermined the typical growth cycle of a microorganism culture usingoptical density measuring means of periodic sampling of themicroorganism culture. The microorganism culture consisted of Number 700bacteria mixture by Sybron Chemicals Inc. A Hewlett Packard 8452A DiodeArray Spectrophotometer operating at a 600 nanometer wavelength of lightwas used to determine the optical density of samples removed from theculture.

Referring now to FIGS. 1 and 5(b), the graphically illustrated resultsof optical density versus time, for a microorganism culture inbio-augmentation apparatus 10, which after approximately three days, wasallowed to reach a cell density midway between its lower and upperexponential growth phase limits as determined and illustrated in FIG.5(a). Upon the microorganism culture reaching a cell densityapproximately midway between its lower and upper exponential growthphase limits, controller 20 was activated to maintain the microorganismculture at substantially such a cell density and deliver microorganismsto an environment to be treated for a period of over approximatelytwenty one days.

Referring to FIGS. 4 and 5(b), during the approximately twenty one days,every 4 hours about 200 cubic centimeters of water, inorganic nutrientsand organic nutrients, was added to the microorganism culture andapproximately 200 cubic centimeters of water, inorganic nutrients,organic nutrients and microorganisms was removed from the microorganismculture and delivered to a grease trap containing grease to bebiodegraded. The water containing inorganic nutrients consisted ofpotassium phosphate, ammonium nitrite, calcium chloride and magnesiumchloride. Specifically, the following is a listing of the relativeamounts of water and inorganic nutrients:

H₂O—1 liter

KH₂PO₄—1 gram

K₂HPO₄—1 gram

NH₄NO₃—1 gram

CaCl₂—0.002 gram

MgCl₂—0.002 gram

A typical grease trap 120 without the use of bio-augmentation apparatus10 requires grease trap 120 to be cleaned every thirty (30) days, and atypical grease trap 120 with the use of bio-augmentation apparatus 10 inoperation requires a grease trap to be cleaned only once a year (365days). Preferably, the microorganism culture is maintained in abioreactor chamber at a concentration of about 500 million cells/cubiccentimeter to about 3 billion cells/cubic centimeter. More preferablythe microorganism culture is maintained in a bioreactor chamber at aconcentration of about 2.5 billion cells/cubic centimeter.

It will be appreciated that microorganism culture 200 can be operated ata greater cell density. However, operating at too great a cell densityrisks having the microorganism culture enter a stationary phase shouldnot enough water, inorganic nutrients or organic nutrients be timelyintroduced. Too low a cell density does not produce enoughmicroorganisms for effective and optimum biodegrading of wastes.Desirably, a cell density midway between its lower and upper limits ofits exponential growth phase is maintained in bioreactor 12.

Method

The method according to the present invention for bio-augmenting thebiodegradation of wastes, comprising the steps of: providing amicroorganism culture, introducing a predetermined supply of water andat least one of inorganic nutrients and organic nutrients to themicroorganism culture, removing a preselected supply of water, at leastone of inorganic nutrients and organic nutrients, and microorganismsfrom the microorganism culture so that the microorganism culture ismaintained in substantially exponential growth, and delivering theremoved preselected supply of water, at least one of inorganic nutrientsand organic nutrients, and microorganisms into contact with anenvironment containing a waste for biodegrading the waste.

It will be appreciated that the present invention is ideally suitablefor use in bio-augmenting the biodegradation of grease in a grease trap,however, the present invention is also amenable to bioremediation ofother waste or waste streams such as lagoons, aeration ponds, soil andground water.

In addition, various means for maintaining and delivering themicroorganisms in an exponential growth rate such as electrically orpneumatically operated solenoids or gravity flow means are equallyapplicable for use in such a bio-augmentation system of the presentinvention.

While only several embodiments of the present invention have been shownand described, it is obvious that many changes and modification may bemade thereunto without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A method for controlling the accumulation of apredetermined waste product thereby maintaining fluid flow in a greasetrap, comprising: a) providing a portable apparatus adapted formaintaining a substantial percentage of the members of a microbialculture in log-phase growth; b) growing a microbiological culture in theapparatus of step a) at the site of a grease trap to be maintained inthe presence of an organic nutrient chemically similar to a wasteproduct the accumulation of which is to be controlled; c) periodicallydischarging an amount of the microbiological culture of step b) into thegrease trap, the amount being effective to control the accumulation ofthe predetermined waste product thereby maintaining fluid flow.
 2. Themethod of claim 1 wherein the predetermined waste product is selectedfrom the group consisting of fat and grease.
 3. The method of claim 1wherein the organic nutrient similar to the predetermined waste productis a water soluble fatty acid.
 4. The method of claim 1 wherein theorganic nutrient is potassium-oleate.